Field-sprayers having vehicle-speed-responsive means for insuring uniform coverage are known (e.g. Hallberg 3,233,832). But no sprayer is known to have a plurality of relatively small auxiliary tanks for holding and mixing-in on-site, the concentrated chemical additives which heretofore have been pre-mixed with the basic liquid in the large tank of the vehicle. Pre-mixing has the decided disadvantage of making it difficult to prevent waste of materials and/or time. If a field is larger than anticipated, a second trip by the driver will be required. If the field is smaller than expected, waste of valuable chemicals will result. In either case the driver may be tempted to detrimentally under-apply or over-apply the dwindling pre-mixed supply. A further disadvantage of conventional pre-mixing is the time-consuming necessity of thoroughly washing-out the tank to remove even traces of chemicals that would be objectionable on a subsequent job.
It is accordingly the principal object of the present invention to provide a field-sprayer tank-vehicle having a plurality of relatively small auxiliary containers for chemical additives for time- and material-saving on-site metered mixing thereof with the tank-carried base liquid.
It is another object to provide such a vehicle having speed-variable positive-acting pumps for each feed line for accurate metering of the several ingredients.
It is a further object to provide such a device with vehicle-speed-responsive means for insuring uniform application of the controlled-quantities mixture.
Other objects and advantages will appear as the following detailed description proceeds.